208 



PLATHELMINTHES 



L. socialis (Leidy). Body very slender and flattened, 25 cm. long 

 and 5 mm. wide, green or brown in color; ventral side lighter than dor- 

 sal ; a single row of 4 to 6 very small eyes on each side of the head and a 

 single pair of larger eyes some distance in front of the others: common 

 from New Jersey to Bay of Fundy, living gregariously under stones, 

 between tide lines; breeds in mid- winter in Long Island Sound. 



L. bicolor Verrill. Body small, 45 mm. long, 1.5 mm. wide, cylin- 

 drical but somewhat flattened, dark green with a mid-dorsal yellowish 

 stripe ; with a single row of 8 to 14 eyes on each side : among algae and 

 hydroids in shallow water in Vineyard and Long Island Sounds; very 

 common in certain localities. 



3. ZYGEUPOLIA C. B. Thompson. Body cylindrical anteriorly and 

 flattened posteriorly; head very long and pointed and without lateral 



sensory grooves; caudal cirrus 

 present: 1 species. 



Z. rubens (Coe) (Z. litoralis 

 C. B. Thorn.*). Body slender 

 and 8 cm. long ; head pure white ; 

 body whitish : coast of New Eng- 

 land; southern California; on 

 sand flats between tide lines. 



4. MICRTJRA Ehrenberg. 

 Small, flat, and soft nemerteans 

 with a caudal cirrus, which can- 

 not swim ; with 3 frontal organs ; ' 

 often with many eyes: about 17 

 species. 



M. caeca Verrill. Body dark 

 brown or yellow ; 10 cm. long and 2 mm. wide ; no eyes : Long Island and 

 Vineyard Sounds, at low-water mark; sexually mature in July and 

 August at Woods Hole. 



M. leidyi (Verr.) (Fig. 336). Body thick anteriorly; flattened pos- 

 teriorly; 15 cm. long and 4.5 mm. wide; red or purple dorsally, usually 

 with a lighter median line and lighter ventrally; proboscis flesh color: 

 common from New Jersey to Cape Ann in the sand near low-water mark; 

 breeds in mid-summer. 



5. CEREBRATTTLUS Renier. Body long, flat, and broad, with a small 

 pointed head and thin edges well adapted for swimming; eyes usually 

 absent; mouth a long slit; with 3 frontal organs; proboscis very long; 

 a caudal cirrus at hinder end: over 60 species; in all seas. 



Fig. 336 



Fig. 337 



Fig. 336 Micrura leidyi (Verrill). 

 Fig. 337 Cerebratulus lacteus (Verrill). 



* See "Zygeupolia litoralis," etc., by C. B. Thompson, Proc. Acad. Nat. Sci., Pbila., 

 Vol. 53, p. 657, 1901. 



